IIS is, in fact, a generic term that covers a number of different servers and services?all of which are responsible for one or more of the following: transferring files, supporting user communication, or publishing information.
IIS is composed of five main components handled by a number of service hosts and individually supported through a number of primary DLL components. You can see the full list in Table 1.1.
Primary DLL Component
World Wide Publishing service (WWW service)
File Transfer Protocol service (FTP service)
Simple Mail Transfer Protocol service (SMTP service)
Network News Transfer Protocol service (NNTP service)
IIS Admin service
Most people will consider the WWW service the primary component of the IIS system, and it will be a core consideration in this book.
For the remainder of this book, I show you the new and changed features in IIS 6. However, there are four main threads to the various improvements made in this latest revision of IIS:
Performance? A brand new method of execution for the IIS component improves performance for static pages, dynamic pages, and especially in the realm of multiple-site installations hosted from a single machine.
Stability? The new execution model also protects individual processes so that problems with a client or a third-party application do not slow down or crash the entire system. An improved Quality of Service (QoS) system can be tuned to improve the reliability of the system without having to manually adjust and optimize different components.
Security? Both the underlying Windows Server 2003 system and the IIS component have had their security systems updated. New locking modes for the IIS component improve basic security, and clients can be authenticated through new ASP.NET, Passport, and delegated authentication models.
Management? The IIS MMC snap-in has been updated not only to handle the new features, but also to make it easier to manage sites?particularly when using multiple virtual sites or when hosting a number of domains. The IIS metabase is now stored entirely in XML, making it easy to modify, update, and replicate configurations.
Taking a wider view of the Application Server role that Microsoft has now applied to the servers that support IIS, we also need to include the integration with .NET technologies. Windows Server 2003 comes with the .NET Framework pre-installed, making it the ideal platform for providing Web services and applications using .NET technology.
.NET FRAMEWORK VERSIONS
Windows Server 2003 comes with version 1.1 of the .NET Framework?applications requiring version 1.0 might still require you to install that version separately. It all depends on exactly how the application was written.
A list of more specific new features, their impact, and the chapters in which they are discussed in more detail are shown in Table 1.2.
Application Health Monitoring
Improves the monitoring capabilities available to administrators for Web applications.
New Request Processor
Separates the IIS server component from the underlying OS and supporting applications, creating a more stable and secure platform that's less vulnerable to request-based attacks.
Dynamic Content Caching
Enables content generated dynamically, which essentially doesn't change, to be cached by IIS for improved performance and lower CPU overhead.
ASP Template Caching
ASP templates are now stored on disk after processing from the ASP file, eliminating the need to recompile ASP templates that have expired from the in-memory cache.
Enables the administrator to assign different applications to different execution pools; if an application fails or ties up the pool, other application pools continue to operate.
Enables ISAPI filters to redirect requests to an alternative URL for processing.
Enables Single Sign On (SSO) facilities for users with a valid Passport.
Low Privilege Execution
IIS now runs under a user with exceptionally low privileges, eliminating another potential weak point in security.
Shuts off all but the most basic static content?with dynamic content having to be specifically and individually enabled, which further reduces potential weak points.
Enables for the easy modification and sharing of the configuration information stored in the metabase just by editing or copying the XML.
Provides integration with the .NET system, including technologies such as Passport and dynamic systems, as well as languages supported by the .NET environment.
IIS 6 can now log using UTF-8 (Unicode) text, useful for foreign language Web sites. A new binary mode makes for a more efficient and performance friendly method of logging compared to the text-base W3C format.
Compression for responses can now be set at a more granular level, enabling compression on individual Web sites or folders instead of the whole server.
Quality of Service
Enables you to configure QoS parameters to prevent individual components of your Web site (IIS, dynamic content, and CPU/memory usage) by those components from affecting other sites and systems.